Perhaps more than any other foreign affairs issue during his tenure, President Barack Obama is being tested by the crisis in Ukraine, where a Russia-designed referendum on the future of Crimea is to be held Sunday.

Can Obama gather the necessary support among European and Asian nations? Will allies and adversaries in Congress join “at the water’s edge” to back his moves? And how will the American public take to yet another problem overseas with national security (and economic) consequences?

“I think the Obama administration has done a good to outstanding job of responding to this … leading from the front … ratcheting up the costs, both economically but also to some of the oligarchs,” conservative New York Times columnist David Brooks said on PBS’s “The Newshour” Friday night.

“At the same time they’re beginning to gather an international coalition to really support Ukraine through the IMF [International Monetary Fund] and elsewhere,” Brooks said of the administration. “I think they’re being very aggressive and very clear. I think they’re responding in a way which is earning bipartisan support.”

Among voters polled on the crisis, there is tentative support for the steps Obama is taking.

A CNN poll last weekend had a plurality of 48 percent approving how Obama has handled Ukraine so far; 43 percent disapproved.

While 52 percent in CNN’s poll are opposed to economic aid for Ukraine, 56 percent favor economic sanctions against Russia. Military aid to Ukraine? The answer is quite clear: More than three-quarters of those polled say “no.”

There is a clear age difference here.

"All demographic groups support economic sanctions except the youngest Americans. More than six in 10 older Americans support sanctions, but 55 percent of Americans under the age of 35 oppose them," polling director Keating Holland said in CNN’s report. "It's possible that generation gap is due to older Americans' memories of the Soviet Union as the chief threat to the US; many younger Americans may have no memory at all of the Cold War and most of those under the age of 25 were not even born when the Soviet Union collapsed."

In a Washington Post-ABC News Poll several days ago, Americans were evenly split (43-42 percent) on the way Obama is handling the situation involving Russia and Ukraine.

But asked “do you support or oppose the United States and its European allies imposing economic sanctions on Russia for its actions involving Ukraine?” a clear 56-31 percent majority voice support.

“Overall, Democrats and Republicans are in rare agreement in supporting sanctions…. Just over six in 10 of partisans in both camps support sanctioning Russia,” the Washington Post reported. “And in an unheard of alignment of the far left and far right, 68 percent of liberal Democrats support sanctions, as do 69 percent of conservative Republicans.”

That age difference found by CNN shows up in the Washington Post-ABC News Poll as well: “Roughly six in 10 Americans who turned 18 while the U.S.S.R. still existed (ages 40 and over) support combined US-European sanctions against Russia. But support for sanctions dips below half among adults age 18 to 39.”

Many Republicans in Congress have chastised Obama on Ukraine.

“We may wish to believe, as President Obama has said, that we are not ‘in competition with Russia,’” Sen. John McCain (R) of Arizona wrote in a New York Times op-ed column Friday. “But Mr. Putin believes Russia is in competition with us, and pretending otherwise is an unrealistic basis for a great nation’s foreign policy.”

McCain urges sending arms and military trainers to Ukraine as soon as possible.

But after more than 10 years of war in Iraq and Afghanistan – fought mainly by younger Americans, it’s worth mentioning – inside “the water’s edge” is where most Americans appear to want their political leaders focused.

“Only 28 percent questioned in the poll say that the country's top priority should be making sure that there is peace and stability throughout the world,” CNN reported. “Nearly seven in ten say the US should emphasize safety and security right here at home.”